The invention is based on a fastening screw and a screw connection with a fastening screw, as well as a method for fastening a body by use of a screw.
In screw connections, many different possibilities of sealing are known between the head of the fastening screw and the opening in the screw through which the screw shaft of the fastening screw is passed.
For instance, it is known to insert a sealing washer for sealing purposes between the retaining face of the screw head and the bearing face of the body to be screwed. To enable the sealing washer to seal properly, the fastening screw must be tightened with a minimum torque. If the fastening screw of the screw connection holds a hollow body against a base body, then the fastening screw cannot be tightened with an arbitrarily high torque, since this would cause excessive deformation of the hollow body. The result of this would be that the fastening screw can be tightened only relatively weakly, so that the minimum torque required for the sealing action is hardly achieved. A further factor is that tightening of the fastening screw, even at a relatively low torque, cannot completely preclude a certain deformation of the hollow body, which can lead to an impairment of the seal between the hollow body and the head of the fastening screw when there is a sealing disk. Another disadvantage of the known screw connection is that after the fastening screw is tightened, settling in the region of the sealing disk between the head of the screw and the bearing face on the hollow body lessens the prestressing in the shaft of the fastening screw somewhat, and as a result the fastening screw is no longer properly tightened, and there is accordingly a risk that the fastening screw will become loose or come undone entirely. Another disadvantage is that the bearing face for the sealing disk on the hollow body must be rather smooth and flat, which increases the effort and expense for manufacturing the body.